Conventionally, in order to supply lubrication to sliding sections of machinery, a surface of each sliding member is coated with a sliding material composition which is to be functioning as a lubricating film in each sliding section. Hence, it is required that the sliding material composition of this kind should be a lubricating film having low friction characteristic, excellent wear resistance so as not to wear out even after a long period of use, and good in fitness with a mating member.
A sliding material composition containing hard powder, a solid lubricant, and a resin binder is known as the conventional sliding material composition (see Patent Documents 1 to 3).